public class operation_arithmetic {
    public static void main(String[] args) {
        int age1=24;
		int age2=18;
		int age3=36;
		int age4=27;
		int sum = age1 + age2 + age3 + age4;
		double avg = sum / 4;
		int minus = age1 - age2;
		int newAge = --age1; 
		
	    System.out.println("年龄总和："+sum);
    	System.out.println("平均年龄："+avg);
		System.out.println("年龄差值："+minus);
		System.out.println("自减后的年龄："+newAge);
    }
}
